Draft gear



June 9, 1942. R. M. NELsoN Filed Oct. 5, 1941 4 SheetS-Sheet 2 INYENTO ber 111. Ne Lsqn/ I i tury/wm;

June 9,` 1942. R. M. ELsoN DRAFT GEAR Filed Oct. 3, 1941 4 Shee'ts-Sheet 3 w z l RobertMNe/s'on, wQ/'QW Patented June 9, 1942 UNITED- STATES PTENT OFFEQE DRAFT GEAR Robert M.

Nelson, Evanston, Ill., assignor to Peerless Equipment Company, Chicago, Ill., a corporation of Delaware 11 Claims.

This invention relates to railway draft gears, and has particular reference to improvements in railway draft gears of the general type comprising a` casing, an annular series of friction shoes therein, resilient means reacting from the casing forwardly upon said shoes, and a wedge element for exerting force rearwardly and outwardly upon said shoes in response to draft and buffing forces imposed on the gear to cause said shoes to frictionally cooperate with the Casing to resist said forces.

In a draft gear of the type mentioned, two or three friction shoes would be the ideal number to employ from the standpoint of maintaining them tight and insuring the effective Cooperation of each of them With the casing. There are, however, certain advantages to empioying more than two or three .friction shoes. For example, from an inertia standpoint, small, light shoes go into action more quickly; the distribution of the load through the shoes to the casing at many points is more uniform, and better contact between the individual shoes and the casing is btained. Besides, there are other advantages which need not be dwelt upon here. Accordingly, itiis the practice in draft gears of the type mentioned to employ more than three friction shoes. When, however, more than three friction shoes are employed, complications arise respecting maintaining all of the shoes tight and insuring effective Cooperation of all of them with the casing, for if the rear ends of certain of the shoes extend even only slightly beyond the rear ends of certain other mentioned shoes may prevent effective Cooperation of the resilient means with the second mentioned shoes. Accordingly, the' general object of the present invention is to provide, in a draft gear of the type mentioned employing more than three friction shoes, simple, practical means to maintain all of the shoes tight and to insure effective Cooperation of all of the same with the casing.

According to the invention, the annular series .of friction shoes is divided into two or more groups of preferahly three, and not more than three, shoes in each group and With the shoes of the respective groups alternating in the series. In addition, there are provided, individual to the respective groups` of shoes, Cap members throughwhich the resilient means acts forwardly uponrthe shoes. Thus, all of the shoes are maintained tight and effective cooperation of all of the shoes with the Vcasing is assured, provided thecap members are of the shoes the first.

tive to the shoes and relatve to each other so that each cap member willat all times cooperate only with the shoes of its related group and not with any other shoe, or shoes. Accordingly, another object of the invention is to provide simple, prac-tical means for accomplishing this last mentioned purpose.

In a draft gear of the type mentioned either a simple resilient means or a plurality of resilient means may be employed to react from the casing forwardlyupon the friction shoes, and in this connection another object of the invention is to provide simple, practical means for distributing the force of the resilient means substantially equally to all of the shoes regardless of the number of the. shoes employed and regardless of whether only a single resilient means or a plurality of resilient means is, or are, employed.

With the foregoing and other objects in view, which Will become more fully apparent as the nature of rthe invention is better understood, the same consists in a draft gear of 'the general type mentoned embodying the novel features of construction, combination and arrangement of parts as will be hereinafter more fully described, illustrated in the accompanying drawings and defined in the appended claims.

In the accompanying drawings, Wherein like characters of f reference denote Corresponding parts in related views:

Figure 1 is a'central; horizontal section through a draft gear constructed in accordance with one practice] embodiment of the invention.

Figure 2 is an enlarged, central, Vertical section through the front end portion of the gear casing showing the internal parts of the gear in elevation.

Figure 3 is a view similar to Fig. 2 showing the internal parts of the gear in section.

Figure 4 is a cross section on the line of Fig. 3.

Figure 5 is a perspoctive view of the cap members showing the same in separated relationship.

Figure 6 is a cross section on the line 5-6 of Fig. 3.

Figures 7 through 12 are views similar to Fig. 3 showing alternative embodiments of the in- Vention.

Figures 13 is a View similar to Fig. 5 showing cap members of alternative form for non-rotative Cooperation with the friction shoes; and

Figure 14 is a detal] perspective view of the rear end portion of one of the friction shoes formed for Cooperation with cap members of the held against rotation relatype shown in Fig. 13.

Referring to the drawings in detail, first with particular reference to Fig. 1, 16 designates a substantially cylindrical casing closed at its rear end and open at its front end and having the front end portion; thereof provided interiorly with rearwardly and inwardly inclined friction surfaces 11; 12 designates an annular series of friction shoes disposed in the front end portion of said casing for frictional Cooperation with said friction surfaces 1|; 13 designates resilient means interposed between the rear wall lt of the casing lt and the rear ends of the friction shoes 12 and reacting from said rear wall upon said friction shoes to tend constantly to urge the same forwardly relative to the casing 1171; 15 designates a wedge element for acting rearwardly and outwardly upon front end portions of said friction V shoes, and 16 designates an assembly-maintaining bolt extending from the rear wall lt of the casing 111 through the wedge element 15 and havi ing a stop nut Il on its front end to limit forward movement of said wedge element relative to said casing so that under the influence of the resilient means 13 and said wedge element the friction shoes 12 are maintained normally in forwardly disposed, outwardly urged positions relative to the casing 11] against the friction surfaces I, all as is common and well known. in the art.

Referring further to Fig. 1, 18 designates side 7 sills of a car underframe structure; 19 and 21] designate front and rear pairs of stop lugs carried by the sills 18 and, in conjunction with said sills, defining a pocket in which the gear is supported by a carrier plate 21; 22 designates a main front follower interposed between the front pair of stop lugs 19 and the wedge element 15; 23 designates a yoke for transmitting draft forces forwardly to the casing 11), and 24 designates a coupler but engaged with the follower 22 for transmitting buffing forces to said follower and through the same to the wedge element 15, all as likewise is common and well known in the art.

Upon draft forces being applied by the yoke 23 to the casing 111 said casing is moved forwardly relative to the friction shoes 12 due to forward movement of said friction shoes being prevented by the front stop lugs 19 acting through the follower 22 and the wedge element 15 and as a consequence, due to the tendency of the inclined surfaces 11 to urge the friction shoes inwardly and to the counter wedging action exerted outwardly upon said shoes by the wedge element 15, said shoes are caused to bear tightly against the friction surfaces I and thus to frictionally resist said forces. On the other hand, upon bufling forces being applied by the coupler butt 211 to the follower 22 and through said follower to the wedge element 15, said wedge element is moved rearwardly and produces rearward movement of the friction shoes 12 relative to the casing i!! due to said casing being held against rearward movement by the rear pair of stop lugs w. At the same time, due to the resistance offered by the resilient means 13 to rearward movement of the friction shoes 12 relative to the casing 13, the wedge element 15 in conjunotion with the inclination of the friction surfaces 11 causes the friction shoes to bear tightly against said friction surfaces and thus to frictionally resist the buffing forces.

Referring now to the features of the invention according to the embodiment thereof illustrated in Figs. 1 to 6, it will be noted that the annular series of friction shoes 12 has, arbitrarily and by way of example, been illustrated as comprising six friction shoes and that of these six shoes, alternate shoes 12a have their rear ends spaced forwardly from the remaining three shoes 12h. In other words, the entire series of shoes comprises two groups of three each with the shoes of the two groups alternating in the series and with the rear ends of the shoes 12a of one group spaced forwardly from the rear ends of the shoes 12h of the other group. It will further be noted that two cap members 25 and 26 are provided through which the resilient means 13 acts forwardly upon the friction shoes.

The cap member 25 comprises a hub 2'1 having extending therefrom three radial arms 28 which are equally spaced apart angularly and which are disposed against the rear ends of the three shoes 12a, respectively. On the other hand, the cap member 26 is in the form of a ring having on its front face three lugs 29 which are equally spaced apart angularly and which are disposed against the rear ends of the three shoes 12h, respectively.

Due to the rear ends of the shoes 12a being disposed forwardly of the rear ends of the shoes 1210 the sides of the latter shoes at their rear ends provide Shoulders with which the arms 28 cooperate to prevent or at least to limit rotation of the cap member 25 relative to the shoes. In this connection the arms 28 may, of course, be sufiiciently narrower than the spaces between the aforesaid Shoulders to permit some slight rotation of the cap member 25 relative to the friction shoes so as not to interfere with free operation of the gear, but in any event the said Shoulders prevent rotation of the cap member 25 relative to the friction shoes in the sense that the arms 28 of said cap member are maintained in cooperative relationship with the rear ends of the shoes 12a and are prevented from engaging the rear ends of the shoes 12h. On the other hand, the arms 28 extend rearwardly beyond the rear ends of the shoes 12 and are disposed between the lugs 29 of the cap member 215. Therefore, the cap member 25 holds the cap member 26 against rotation relative to the friction shoes in the same sense as said cap member 25 is held against rotation relative to said shoes and, as a consequence, the lugs 29 are maintained in cooperative relationship with the rear ends of the shoes 12b and are prevented from engagng the rear ends of the shoes 12a.

The hub 21 of the cap member 25 is alined with the central opening in the ring of the cap member 25 and may extend into said opening to be engaged by the resilient means 13, and the three-point engagement of each of the cap members 25, 25 with the three friction shoes of its related group assures that all of said shoes will be urged forwardly by the resilient means 13 which cooperates with both of said cap members. Obviously, therefore, all'of the shoes are maintained normally tight and effective cooperation of all of the shoes with the casing 18 in resisting draft and bufiing forces imposed on the gear is assured.

The resilient means 13 may comprise, as usual, and as shown in the present instance, a plurality of coil Springs disposed in nested relation- 'ship to each other, and in that event one or more of said coil springs may cooperate with one of the cap members 25, 26 and not with the other of said cap members, and one or more other of said coil Springs may cooperate with the other of said cap members and not with the first mentioned cap member. In that case, the Springs may be designed so that they exert approximately equal forces forwardly against the respective cap members and the shoes. Alternatively, the spring, or springs, engaged with the cap member 28 may be Stronger than the spring, or springs, engaged with the cap member 25 and in that event suitable resilient means 30 may be interposed between the cap members 25 and 26 as illustrated in Figs. 8, 9 and 10 so that the stronger spring force exerted against the cap member 26 will be transmitted through said cap member to the cap member 25 to augment the weaker spring force exerted against the latter member. As a further alternative in this respect, Fig. 11 illustrates that a disk 3| may be provided to be urged forwardly by the resilient means |3 and that between this disk and the cap members 25, 25 may be interposed suitable resilient means 32 engaged with both of said cap members so that the total force of the resilient means IS is distributed substantially equally to said cap members. Fig. 12 illustrates a similar arrangement in which the resilient means 13 comprises a series of alternating metal disks 33 and rings 34 of rubber or equivalent resilient material and in which the forwardmost resilient ring 34 engages both of the cap members 25 and 26 and serves the same purpose as the resilient means 32 of the Fig. 11 arrangement.

According to Figs. 7 to 14 the constructions differ from the Figs. 1 to 6 construction in that the rear ends of all of the friction shoes |2 are disposed approximately in a common plane transversely of the gear and ribs 35 are pro- Vided on the arms 28 and the lugs 29 of the cap members 25 and 26 to fit into recesses 33 provided in the rear ends of the shoes |2 to hold said cap members against rotation relative to said shoes. This construction may be employed in the Figs. 1 to 6 form of the invention in lieu of having the rear ends of the shoes of one group spaced forwardly from the rear ends of the shoes of the other group or, oonversely, the

Figs. 1 to 6 construction for preventing rotation of the cap members 25, 26 relative to the shoes may be employed in the Figs. 7 to 12 constructions in lieu of recessing the rear ends of the shoes and providing ribs on the arms and the z lugs of the cap members to fit into the recesses in the shoes. Obviously, the rear ends of the shoes, instead of being recessed, may be provided with ribs, and the arms and lugs of the cap members, instead of ribs, may be recessed to accommodate the ribs on the rear ends of the shoes, this simply being the reverse of the construction illustrated in Figs. 7 to 14.

Referring to Fig. 7, the construction therein illustrated is the same as the construction illustrated in Figs. 1 to 6, except that the rear ends of all of the friction shoes are disposed in approximately a common plane transversely of the gear and interfitting rib and reoess means between the friction shoes and the arms and the lugs of the cap members are provided to hold said cap members against rotation relative to said shoes. In this connection, while Fig.` 7 shows an intertting rib and recess means between each of the shoes and its related arm or lug, it is obvious that any means between any one of the shoes and its related arm or lug to hold the related cap member against rotation relative to the shoes Will serve all purposes of being provided With s.

` shoes divided groups alternating in the series, a wedge the invention in this respect. I-Iowever, from a practical manufacturing and assembly standpoint it is preferable that-all of the friction shoes be duplicates of one another regardless of whether there are interfitting connections between all of them and all of the arms and lugs of the cap members or between any one or more of them and any one or more of the arms or lugs of said cap members. Further in this connection it is a feature of the invention that the arms and the lugs of the cap members engage the rear ends of the shoes and that the arm and lug engaged rear end portons of the shoes are disposed equal distances outwardly from the longitudinal axis of the casing IO, Whereby the force of the resilient means |3 is applied most advantageously to the shoes.

Referring to Fig. 8, the construction is generally the same as the Fig. '7 construction except that the lugs 29 are longer to provide the necessary space between the cap members 25 and 26 to accommodate the resilient means 30, which means may comprise, for example, pads of rubber or the like interposed between the arms 28 and the ring portion of the cap member 26 between the lugs 29 thereof.

Referring to Fig. 9, the construction is generally the same as the Fig. 8 construction, except that the resilient means 13 is engaged solely with the cap member 25 and the force of said resilient means is transmitted to the cap member 25 through a resilient pad of rubber or other suitable material` interposed between said cap members.

Referring to Fig. 10, the construction is the as in Fig. 9, except that the resilient means interposed between the cap members 2 and 26 comprises dished spring disks instead of pads of rubber or the like.

While the present gear has been illustrated in the present instance as comprising six friction into two groups of three shoes each, it is apparent that the gear may comprise a total number of shoes other than six and that the shoes may be divided into two or -more groups with a cap member individual to each group.

Without fnrther description it is thought that the features and advantages of the invention will be readily apparent to those skilled in the art, and it will of course be understood that changes inthe form, proportion minor details of con- Strnction be resorted to, Without departing from the sjgirit of the invention and scope of the appended claims.

I claim:

1. A draft gear comprisine a casing, an annular series of friction shoes in said casing divided into two groups with the shoes of the respective element having wedging Cooperation with front end portions of said shoes for exerting force rearwardly and outwardly upon shoes to urge them outwardly into frictional cooperati-on i' casing, a first cap member engaged with end of the shoes of one group not With the shoes of the other group, a second cap member engaged with rear end portons of the shoes of the other group and not with the shoes of the rst mentioned group, resilient means reacting from the casing forwardly upon said cap memhers, means whereby at least one of said cap members is held against rotation relative to shoes, and interfitting formations on said cap members holding said cap members against rotation relative to each other, whereby each cap member is maintained in cooperative relationship with the'shoes of its related group to the exclusion of the shoes'of the other group.

2. A draft gear comprising a casing, an annular series of friction shoes in said casing divided into two groups with the'shoes of the respective groups alternating in the series, a wedge element having wedging cooperation with front end portions of said shoes for exerting force rearwardly and outwardly upon said shoes to urge them outwardly into frictional cooperation with said casing, a first cap member engaged with rear end portions of the shoes of one group and not with the shoes of the other group, a second cap member engaged with rear end portions of the shoes of the otherv group and not with the shoes of the first mentioned group, the engagements of both cap members with their related shoes being at equal distances outwardly i from the longitudinal axis of the casing, resilient means reacting from the casing forwardly upon said cap members, means whereby at least one of said cap members is held against rotation relative to said shoes, and interfitting formations on said cap members holding said cap members against rotation relative' to each other, whereby each cap member is maintained in cooperative relationship with the shoes of its related group to the exclusion of the shoes of the other group.

3. A draft gear comprising a casing, an annular series of friction shoes in said casing divided into two groups With the shoes of the respective groups alternating in the series, a wedge' element having wedging Cooperation with front end portions of said shoes for exerting force rearwardly and outwardly uponV said shoes to urge them outwardly into frictional Cooperation with said casing, a first cap member having lugs engaged With rear end portions of the shoes of one group and not with the shoes of the other group, a second cap member having arms engaged with rear end portions of the shoes of the other group and not with the shoes of the first mentioned group,

the arms of said second cap member being disposed between the lugs of said first cap member whereby said cap members are held against rotation relative to each other, resilient means reacting from the casing forwardly upon said cap members, andmeans Whereby at leastione of said cap members is held against rotation relative to said shoes whereby each cap member is maintained in cooperative relationship with the shoes of its related group to the exclusion of the shoes of the other group.

4. A draft gear comprising a casing, an annular series of friction shoes in said casing divided into two groups with the shoes of the respective groups alternating in the series, the rear ends of the shoes of one group being spaced forwardly from the rear ends of the shoes of the other` group, a wedge element having wedging Cooperation with front end portions of said shoes for exerting force rearwardly and outwardly upon said shoes to' urge them into frictional cooperation with said casing, a first cap member having arms engaged with the rear ends of the shoes of the first mentioned group and not with the shoes of the second mentioned group, said arms being disposed betweenthe rear end portions of the shoes of the second mentioned group Whereby said cap member is held against rotation relative to the shoes, a second cap member engaged With the rear ends of the shoes of the second mentioned group and not with the shoes of first mentioned group, resilient means reacting from the casing forwardly upon said cap members, and means holding said second mentioned cap member against rotation relative to said first mentioned cap member whereby each cap member is maintained in cooperative relationship to the shoes of its related group the shoes of the other group.

5. A draft gear comprising a casing, an annular series of friction shoes in said casing divided into two groups with the shoes of the respective groups alternating in the series, the rear ends of the shoes of both groups being disposed in substantially a common plane transversely of the casing, a wedge element having wedging cooperation With front end portions of said shoes for exerting force rearwardly and outwardly upon said shoes to urge them outwardly into frictional cooperation with said casing, a first cap member engaged with the rear ends of the shoes of one group and not with the shoes of the other group, a second cap member engaged with the rear ends of the shoes of the other group and not with the shoes of the first mentioned group, resilient means reacting from the casing forwardly upon said cap members, means Whereby at least one of said cap members is held against rotation relative to said shoes, and interfitting formations on said cap members holding said cap members against rotation relative to each other, Whereby each cap member is maintained in cooperative relationship with the shoes of its related group to the exclusion of the shoes of the other group.

6. A draft gear comprising a casing, an annular series of friction shoes in said casing divided the 75 into two groups with the shoes of the respective groups alternating in the series, a wedge element having wedging Cooperation With front end portions of said shoes for exerting force rearwardly and outwardly upon said shoes to urge them out- Wardly into frictional Cooperation With said casing, a rst cap member engaged With rear end portions of the shoes of one group and not with the shoes of the other group, a second cap member engaged with rear end portions of the shoes of theother group and not with the shoes of the first mentioned group, resilient means reacting from the casing forwardly upon said cap members, means coacting with said resilient means and said cap members whereby the force of said resilient means is distributed approximately equally to the two cap members, means whereby at least one of said cap members is held against rotation relative to said shoes, and interfitting formations on said cap members holding said cap members against rotation relative to each other, whereby each cap member is maintained in cooperative relationship With the shoes of its related group to the exclusion of the shoes of the other group. 7. A draft gear comprising a casing, an annular series of friction shoes in said casing divided into two groups with the shoes of the respective groups alternating in the series, a Wedge element having weolging Cooperation With front end portions of said shoes for exerting force rearwardly and outwardly upon said shoes to urge them outwardly into frictional cooperation With said casing, a first cap member engaged with rear end portions of the shoes of one group and not with the shoes of the other group, a second cap memto the exclusion of casing forwardly upon said cap members, means coacting With said resilient elements and said cap members whereby the combined force of said plurality of resilient elements is distributed approximately equally to the two cap members, means whereby at least one of said cap members is held against rotation relative to said shoes, and interfitting formations on said cap members holding said cap members against rotation relative to each other, whereby each cap member is maintained in cooperative relationship with the shoes of its related group to the exolusion of the shoes of the other group.

8. A draft gear comprising a casing, an annular series of friction shoes in said casing divided into two groups with the shoes of the respective groups alternating in the series, a Wedge element having wedging cooperation with front end portions of said shoes for exerting force rearwardly and outwardly upon said shoes to urge them outwardly into frictional cooperation with said casing, a first cap member engaged with rear end portions of the shoes of one group and not with the shoes of the other group, a second cap member engaged with rear end portions of the shoes of the other group and not with the shoes of the first mentioned group, resilient means reacting from the casing forwardly upon one of said cap members, resilient means between said cap members for transmitting the force of said first mentioned resilient means to the other cap member, means whereby at least one of said cap members is held against rotation relative to said shoes, and interfitting formations on said cap members holding said cap members against rotation relative to each other, whereby each cap member is maintained in cooperative relationship with the shoes of its related group to the exclusion of the shoes of the other group.

9. A draft gear comprising a casing, an annular series of friction shoes in said casing divided into two groups with the shoes of the respective groups alternating in the series, a wedge element having wedging cooperation with front end portions of said shoes for exerting force rearwardly and outwardly upon said shoes to urge them outwardly into frictional cooperation with said casing, a first cap member engaged with rear end portions of the shoes of one group and not with the shoes of the other group, a second cap member engaged with rear end portions of the shoes of the other group and not with the shoes of the first mentioned group, resilient means reacting from the casing forwardly upon said cap members, interfitting rib and recess means between at least one of said cap members and at least one of the shoes of the related group holding said cap member against rotation relative to said shoes, and interfitting formations on said cap members holding said cap members against rotation relative to each other, whereby each cap member is maintained in cooperative relationship with the shoes of its related group to the exclusion of the shoes of the other group.

10. A draft gear comprising a casing, an annular series of friction shoes in said casing divided into two groups with the shoes of the respective groups alternating in the series, a wedge element having Wedging cooperation with front end portions of said shoes for exerting force rearwardly and outwardly upon said shoes to urge them out- Wardly into frictional cooperation with said casing, 'a first cap member engaged with rear end portions of the shoes of one group and not with the shoes of the other group, a second cap member engaged with rear end portions of the shoes of the other group and not with the shoes of the first mentioned group, resilient pad means disposed against the rear ends of both of said cap members, a stiif ring disposed against the rear of said pad means, resilient means reacting from said casing forwardly upon said ring and through said pad means to tend to urge both cap members forwardly relative to said casing, said ring and pad means acting to distribute the force of said resilient means approximately equally to said cap members, means whereby at least one of said cap members is held against rotation relative to said shoes, and interfitting formations on said cap members holding said cap members against rotation relative to each other, whereby each cap member is maintained in cooperative relationship with the shoes of its related group to the exclusion of the shoes of the other group.

11. A draft gear comprising a casing, an annular series of friction shoes in said casing divided into two groups with the shoes of the respective groups alternating in the series, a Wedge element having wedging cooperation with front end portions of said shoes for exerting force rearwardly and outwardly upon said shoes to urge them outwardly into friotional cooperation with said casing, a pair of cap members interlocked with each other against rotation relative to each other, each of said cap members being engaged with rear end portions of the shoes of one group and not with the shoes of the other group, resilient means reacting from the casing forwardly upon said cap members, and means holding said cap members and said shoes against rotation relative to said shoes.

ROBERT M. NELSON. 

